Latch for electric switches



0a. 27, 1925. 1,558,651 J, 5. THOMPSON LATCH FOR ELECTRIC SWITCHES Filed May 11, 1925 Flfimln FIE-5-2..

INVENTOR Jessy/7.5T Fro/77,0300

% ATTORNEYS Patented Oct. 27, 1925.

UNITED STATES JOSEPH S. THOMPSON, OF SAN FRANCISCO, CALIFORNIA.

LATCH FOR ELECTRIC SWITCHES.

Application filed May 11, 1925.

T 0 all 10/1097), it may concern:

Be it known that I, J osnrri S. THOMPSON, a citizen of the United States, and aresident of the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Latches for Electric Switches, of which the following is a specification.

This invention relates to latches for electric switches. More particularly it relates to latches for electric switches of the knife or blade type. In switches of this character it is desirable to lock the same in their closed position, not only to insure a good contact but to prevent their opening at undesired times. This is particularly true where the switches'are mounted on moving bodies or are in other positions subject to vibration.

An object of the invention is to provide an improved device of this character which is of rugged and simple construction and which will operate in a safe and reliable manner.

The invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following description, where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings 1 have shown a form of device embodying my invention but it is to be understood that I do not limit myself to such form since the invention as set forth in the claims may be embodied in a plurality of. other forms.

In the drawings:

Figure 1 is a side elevation of a switch embodying my invention with the latch shown in closed position.

Fig. 2 is a section taken on the line 2-2 of Fig. l, and

Fig. 3 is a section taken on the line 3-3 of Fig. 1 but also showing a switch opening member and the switch in open or unlocked position.

Referring to the drawings in which 1 indicates a base which supports a pair of fixed contacts 2, 2 in the usual manner. The base 1 also supports a fixed lug 3. which cooperates with my improved latch as will here inafter be described. The lug 3 is preferably positioned on the parts supporting the contacts 2, 2, as shown although it is ob- Serial No. 29,283.

vious that this lug could be placed in numerous other positions on the base 1. The numeral 4 indicates a switch blade which is pivotally connected to a terminal in a manner readily understood and not shown in the drawings. The free end of the switch blade at which extends beyond the contacts 2, 2 is provided with my improved latch mechanism which consists of a ring 5 or other suitable member having a central opening which is riveted or otherwise suitably secured to the said blade as indicated at 6 in Fig. 1. The ring 5 is shown in section in Fig. 2 and its inner periphery is indicated in dotted lines in Fig. 1. At its edge opposite the rivets 6 the ring is provided with suitable lugs or cars 7 on which a door 8 is pivoted or hinged. The door 8 preferably has a solid surface, is substantially the same size as the ring 5 and is pivoted to said ring by means of a bolt 9 in a manner readily understood. A spring 10 is provided normally to urge the door against the ring 5 or in its closed position. The door 8 swings inwardly toward the lug 3 on its hinge in a plane at right angles to the movement of the blade 4. about its pivot. On its surface adjacent the ring 5 the door 8 is preferably provided with a lug 11 which passes over the inner periphery of said ring and assists in positioning and holding the door in its closed position. The door 8 is also provided with a hook or latch member 12 as shown in Fig. 2 which is arranged to pass underneath the lug 3 and thereby lock the blade 4 in, its closed position as shown in Fig. 1. In Fig. 3 the door is indicated in its closed position by dotted lines and in its open position by full lines. WVhen the switch is in its closed position, as shown in Fig. 1, the same may be opened by means of an opening member 13, shown in Fig. 3. The member 13 is inserted through ring 5, thereby engaging the door 8 andv swinging the same upon its hinge, which disengages latch 12 from lug 3, and unlocks the switch, which may then be pulled open, or thrown to its opposite position, if the switch is of the double throw type. It is of course apparent that my invention .is equally adaptable for double throw switches, in which case the other set of tired contacts is also provided with a lug similar to lug 3, and the door 8 is provided with another latch 12 to cooperate with said lug.

What I claim and desire to secure by United States Letters Patent is:

1. A device of the character described.

hinged catch carried on the-. free-end-of said blade adapted to swing in a plane at right angles to the movement of said blade andl engage said element.

2. A device oi" the character described comprising a base, a switch blade pivoted thereon, cooperating fixed contacts on said; base positionedv inter-mediate thecpivot o't;

said blade and its free end, a fixed element on said base intermediate said contacts and.

the free end-0t said-tblade, and a hinged catch carried on the free-end of said blade adapted to swing in a plane at. right'anglesto the movement of said blade and engage said fixed element thereby locking said blade'in closed position on said contacts.

A device of the character described comprising a pivoted switch blade,cooperating fixed contactsthereior and meansioiwlocking said blade inclosed position comprising a fixed element independent of said blade and latching means carried onythe-t'rew end of said blade comprising a ring-formedzi element secured to the free end of said blade and a member pivot-ed on said'ringiormedclement havinga projectionadapted to ensaid fixed element.

at. A device of the character described comprisinga pivoted switch blade, cooperating fixed contacts therefor and means for locking said blade in closed position comprising a fixed element independent of said bladeand latchiiig i'ieans carried on the free end of said blade comprising a ring-formed element secured to thefreeend of said blade ands-a member-pivoted on said ring.-;fori1'ied element arranged to swing inwardly over said ringstormed :menibcr having a projection adapted to engagesaid fixed element.

5. A device of the character comprising ,a pivoted switch blade, cooperating fixed contactsv therefor and means for lockin said blade lnwClOSGd I )ositioni com- I a o v u I prising a fixed element independent 0t :saldi blade and latchingimeanscarried on the free end of said bladecomprising a ring-formedelementsecured tothe free end otisaid blade and amember-pivoted on said ringsformeda element arranged=- to swing inivardlw over; said ring-formed member :in a plane at might-r angles to the movement of said blade-having,- a projection adapted toiengagesaidsfixed element.

In t6SlZ1,1I10I1 Wll8reOii,iI have-hereunto set my hand.

' JOSEP-I-LS. THOMPSON;

described 

